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authorEthan Solomita <solo@google.com>2007-07-15 23:38:16 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-16 09:05:36 -0700
commit462e00cc7151ed91fba688594436c453c80efb5d (patch)
treebf648899ba65f9eb000e9c8163a61c1cb1be9bfe /mm/memory.c
parentb71636e29823c0602d908a2a62e94c9b57a97491 (diff)
downloadlwn-462e00cc7151ed91fba688594436c453c80efb5d.tar.gz
lwn-462e00cc7151ed91fba688594436c453c80efb5d.zip
oom: stop allocating user memory if TIF_MEMDIE is set
get_user_pages() can try to allocate a nearly unlimited amount of memory on behalf of a user process, even if that process has been OOM killed. The OOM kill occurs upon return to user space via a SIGKILL, but get_user_pages() will try allocate all its memory before returning. Change get_user_pages() to check for TIF_MEMDIE, and if set then return immediately. Signed-off-by: Ethan Solomita <solo@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c
index ee2925998e2e..cfddcd2075b9 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1055,6 +1055,14 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
do {
struct page *page;
+ /*
+ * If tsk is ooming, cut off its access to large memory
+ * allocations. It has a pending SIGKILL, but it can't
+ * be processed until returning to user space.
+ */
+ if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE)))
+ return -ENOMEM;
+
if (write)
foll_flags |= FOLL_WRITE;